Microwaves and infrared thermography — Comparative studies in early breast cancer detection

The paper presents some recent advances concerning a non-invasive microwave method used to investigate living structures. An overview of the main investigation methods in breast cancer are presented, as well as their classification. Thermography as an early non-invasive and highly sensitive method helps on the detection of the malign tumours in the early curable stages, contributing to diminish the mortality which appears in the cases where the breast cancer was detected in tardive incurable stages. Infrared imaging of the breast has shown effective results in both risk assessment and prognostic determination of breast cancer. It is a non-invasive investigation method for the living structure which uses the radiation emitted by the biological structures themselves within the microwave range, according to the radiation laws of electromagnetic waves. The microwave radiometry allows for the depth malignant structures detection because the microwaves have a greater wavelength and are less absorbed by the tissue traversed from the tumor to the surface. The temperature resolution is compatible with that of infrared thermography (0.1 °C). The resolution is connected to the fact that the difference between the environmental temperature (25 °C) and the measured body temperature average (37 °C) is relatively small. In the microwave range the intensity of electromagnetic radiation is almost 10⁶ less than infrared radiation. Images obtained by radiometric methods for tumor structures detection are distribution maps of electrical properties of tissues. We propose an automated approach to detect asymmetric abnormalities in thermograms.